Digestion

Large intestine

- Water absorption - Waste for egestion (removal) from the body

Gall Bladder

- stores bile - Gallstones can form here

How do mechanical and chemical digestion work together to break down food?

Mechanical digestion by the mouth, stomach, and bile break up large chunks of food into smaller pieces. This increases the surface area for enzymes to act to chemically break down carbohydrates, fats, and proteins into sugars, fatty acids, and amino acids.

What two organs help break down food mechanically?

Mouth and stomach

Peristalsis

Muscular contractions that push food through the digestive system

Esophagus

Muscular tube connecting the throat and stomach

Anus

Opening through which wastes are eliminated

Parietal cell

Produces hydrochloric acid in the stomach

In humans, the large intestine is the major site for the

absorption of water into the bloodstream

In humans, a major disadvantage of having a small intestine the same shape as the stomach would be that the

absorptive surface area would be decreased

What represents fat globules to fat droplets?

emulsification

What are the two types of animal systems?

incomplete digestive system and complete digestive system

What is the process where an animal sucks up food through a hole?

ingestion

A student has a hamburger, french fries, and soda for lunch. Which sequence represents the correct order of events in the nutritional processing of this food?

ingestion - digestion — absorption → egestion

Where does most water absorption occur?

large intestine

Digestion

process that breaks down food

Egestion

removal of waste

after a person's stomach was surgically removed, the chemical digestion of the ingested protein would probably begin in the

small intestine

Most absorption of digestive end products into the bloodstream occurs in this organ

small intestines

Complete digestive system

two openings (mouth and anus) Ex: earthworm

WHAT IS THE ROLE OF GASTRIN IN DIGESTION?

GASTRIN IS A HORMONE SECRETED BY THE STOMACH THAT INDUCES GLANDS TO PRODUCE HYDROCHLORIC ACID FOR DIGESTION.

HOW DOES ACID AFFECT PEPSINOGEN?

HYDROCHLORIC ACID CHANGES INACTIVE PEPSINOGEN INTO ACTIVE PEPSIN TO START PROTEIN DIGESTION IN THE STOMACH.

Which is the correct statement that matches with the food getting swallowed down the esophagus?

It transports nutrients within the digestive tract.

During chemical digestion, large food molecules are broken down to smaller food molecules by the process of

hydrolysis

What are the two types of digestion?

intracellular and extracellular

Adult humans normally produce feces with low water content due to the activities of the

large intestine

Digestive enzymes which hydrolyze molecules of fat into fatty acid and glycerol molecules are known as

lipases

Enzymes which speed up the hydrolysis of fats are known as

lipases

What are the secretary organs?

liver and pancreas

Incomplete digestive system

one opening (mouth or oral cavity) Ex: starfish

The chemical digestion of carbohydrates begins in this organ

oral cavity

extracellular digestion

outside of the cell - enzymes are secreted into a digestive cavity where food is broken down and the nutrients are passed to cells Ex: animals

What organ produces the three enzymes needed to breakdown food?

pancreas

What are the two parts of digestion?

physical and chemical

The principal function of mechanical digestion is the

production of more surface area for enzyme action

The complete hydrolysis of carbohydrates results directly in the production of

simple sugars

Which are produced as a result of the mechanical digestion of a piece of meat?

smaller meat particles

The chemical digestion of protein usually begins in this organ

stomach

Which process in humans would be most directly affected if peristalsis were to stop?

the movement of food through the gastrointestinal tract

intracellular digestion

within the cell - the enzymes break down food into small molecules the cell can use Ex: Plants

Stomach

- Breaks down food into a paste-like consistency - Contains hydrochloric acid (pH near 2) - Hormone gastrin is produced to stimulate acid production - Secrets pepsin (active form of pepsinogen) to begin protein digestion - Mucus lining for protection - Sores called ulcers can form

Mouth

- Ingestion of food - Physical digestion - Beginning of carbohydrate digestion (salivary amylase from the salivary glands)

Pancreas

- Produces pancreatic juice to make the small intestine basic (pH near 8) - Releases the enzymes pancreatic amylase (carbs), trypsin (proteins), lipase (lipids) into the small intestine

Chemical

- breaking down of complex molecules into smaller ones (carbs, lipids, and proteins)

Physical

- large pieces are broken into smaller ones - also known as mechanical Ex: both earthworms and and birds use a gizzard to grind up food using sand or stones

Small intestine

- nutrient absorption of digestive end products (monomers) into the blood through structures called Villi - basic environment near (pH 8) - Hormone produced is secretin (which stimulates the pancreas to secrete pancreatic juice

Liver

- produces and releases bile to emulsify (breakdown from large to small) lipids

Esophagus

A tube of the pharynx that contracts (called peristalsis) to push food to stomach

EXPLAIN THE DIGESTION OF CARBOHYDRATES. BE SURE TO INCLUDE THE REGIONS OF THE DIGESTIVE TRACT WHERE CARBOHYDRATE DIGESTION OCCURS.

DIGESTION OF CARBOHYDRATES BEGINS IN THE MOUTH. THE ENZYME AMYLASE CONTAINED IN SALIVA BREAKS DOWN BONDS IN STARCH MOLECULES AND ADDS WATER TO THE FOOD. NO FURTHER CARBOHYDRATE DIGESTION OCCURS IN THE STOMACH DUE TO ITS ACID PH. COMPLETION OF DIGESTION TAKES PLACE IN THE SMALL INTESTINE, RESULTING IN THE FORMATION OF GLUCOSE.

EXPLAIN HOW DIGESTIVE SYSTEMS IN DIFFERENT MULTICELLULAR ANIMALS ARE ADAPTIVE.

DIGESTIVE SYSTEMS IN MULTICELLULAR ANIMALS ARE ADAPTED TO THE ANIMAL'S DIET. FOR EXAMPLE, STOMACH OF COWS, HORSES AND RABBITS HAVE SIDE POCKETS THAT CONTAIN MICROORGANISMS THAT AID IN THE DIGESTION OF CELLULOSE IN THEIR DIETS. SINCE MEAT IS EASIER TO DIGEST, THE DIGESTIVE TRACT OF CARNIVORES ARE RELATIVELY SHORT.

Amylase

Enzyme that breaks down starches into simple carbohydrates

Pepsin

Enzyme that starts to digest proteins in the stomach

BRIEFLY SUMMARIZE THE MOVEMENT OF FOOD THROUGH THE HUMAN DIGESTIVE TRACT.

FOOD ENTERS THE ORAL CAVITY AND PROCEEDS PAST THE EPIGLOTTIS DOWN THE ESOPHAGUS TO THE STOMACH. AFTER BEING LIQUIFIED IN THE STOMACH, THE FOOD TRAVELS THROUGH THE SMALL INTESTINE (WHERE NUTRIENT ABSORPTION OCCURS) THEN THE LARGE INTESTINE(WHERE WATER ABSORPTION OCCURS). PARTS OF THE FOOD THAT REMAIN UNDIGESTED ARE ELIMINATED THROUGH THE ANUS AS FECES.

Are fat molecules easy to break down?

Fat molecules can be difficult to break down because large fat droplets do not mix well with water-based enzymes such as lipase. For lipase to work, it helps if the fat is emulsified into tiny droplets. This is done with the help of bile, which is stored in the gallbladder.

Epiglottis

Flap to cover trachea or airway

Bile

Chemical that breaks up large fat droplets

WHAT IS THE ROLE OF THE SMALL INTESTINE IN THE DIGESTION OF PROTEINS AND FATS?

WHEN PROTEINS ENTER THE SMALL INTESTINE, THEY ARE ACTED ON BY PANCREATIC JUICE THAT RAISES THE PH SO THAT ENZYMES SUCH AS TRYPSIN CAN BREAK PEPTIDE BONDS TO PRODUCE AMINO ACIDS FROM POLYPEPTIDES. WHEN FATS ENTER THE SMALL INTESTINE, THEY ARE MIXED WITH BILE THAT BREAKS DOWN FAT DROPLETS INTO SMALL PARTICLES THAT CAN BE FURTHER BROKEN DOWN BY ENZYMES SUCH AS LIPASE.

Which substances are released into the small intestine of a human and aid in the digestion of the intestinal contents?

bile, pancreatic juice, and intestinal juice